Traynor Mark 3

[makinrose]

I replaced the dynamite-stick filter caps with modern electrolytics rated for the same voltage (450V).

B+ is right around 452 Vdc, and so I'm concerned that I don't have enough "safety margin' (even though the original 450V caps lasted for 45 years or so). Should I install a pair of 250V in series for the first reservoir cap?

Amp now sounds much stronger.

I'd be worried about it. My guess is that the voltage is higher than it would have been when wall voltages were lower but I'm not a Traynor expert by any stretch.   You could use higher voltage caps or caps in a series.  Another possibly would be to add a voltage clamp circuit or kit  to it to ensure the voltage will not be too high. I'm sure Kevin will have some thoughts on it too.....